import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';

// Square组件不再持有state  从Board组件中接收值，并且通知Board组件。
// 在React术语中Square组件称做“受控组件”
// class Square extends React.Component {
//   render() {
//     console.log(this.props)
//     return (
//       <button
//         className="square"
//         onClick={() => this.props.onClick()}>
//         {this.props.value}
//       </button>
//     );
//   }
// }

// 只有render方法 无state  可以简化写成函数来调用
function Square(props) {
  return (
    <button className="square" onClick={props.onClick}>
      {props.value}
    </button>
  )
}

class Board extends React.Component {
  // constructor(props) {
  //   super(props)
  //   this.state = {
  //     squares: Array(9).fill(null),
  //     xIsNext: true
  //   }
  // }

  // handleClick(i) {
  //   // 添加了一份副本而不是直接修改数据
  //   const squares = this.state.squares.slice()
  //   // 填充过格子或者有玩家胜出 停止
  //   if (squares[i] || calculateWinner(squares)) {
  //     return
  //   }
  //   squares[i] = this.state.xIsNext ? 'x' : 'o'
  //   this.setState({
  //     squares: squares,
  //     xIsNext: !this.state.xIsNext
  //   })
  // }

  renderSquare(i) {
    return (
      <Square
        value={this.props.squares[i]}
        onClick={() => this.props.onClick(i)}
      />
    )
  }

  render() {
    // const status = 'Next player: ' + (this.state.xIsNext ? 'x' : '0');
    // const winner = calculateWinner(this.state.squares)
    // let status
    // if (winner) {
    //   status = 'Winner：' + winner + '!!!!!'
    // } else {
    //   status = 'Next player：' + (this.state.xIsNext ? 'x' : 'o')
    // }

    return (
      <div>
        {/* <div className="status">{status}</div> */}
        <div className="board-row">
          {this.renderSquare(0)}
          {this.renderSquare(1)}
          {this.renderSquare(2)}
        </div>
        <div className="board-row">
          {this.renderSquare(3)}
          {this.renderSquare(4)}
          {this.renderSquare(5)}
        </div>
        <div className="board-row">
          {this.renderSquare(6)}
          {this.renderSquare(7)}
          {this.renderSquare(8)}
        </div>
      </div>
    );
  }
}

class Game extends React.Component {
  constructor(props) {
    super(props)
    this.state = {
      history: [{
        squares: Array(9).fill(null)
      }],
      xIsNext: true,
      stepNumber: 0
    }
  }
  // 点击方格子
  handleClick(i) {
    // const history = this.state.history
    // 重点！！！！
    const history = this.state.history.slice(0, this.state.stepNumber + 1)
    const current = history[history.length - 1]
    const squares = current.squares.slice()
    // 填充过格子或者有玩家胜出 停止
    if (squares[i] || calculateWinner(squares)) {
      return
    }
    squares[i] = this.state.xIsNext ? 'x' : 'o'
    this.setState({
      history: history.concat([{
        squares: squares
      }]),
      stepNumber: history.length,
      xIsNext: !this.state.xIsNext
    })
  }
  // 回退走的棋
  jumpTo(step) {
    console.log(step)
    this.setState({
      stepNumber: step,
      xIsNext: (step % 2) === 0 // 偶数时，改变状态？？？？
    })
  }

  render() {
    const history = this.state.history
    const current = history[this.state.stepNumber]
    const winner = calculateWinner(current.squares)

    const moves = history.map((step, index) => {
      console.log(step, '--', index)
      const desc = index ?
        'go to move #' + index :
        'go to game start'
      return (
        <li key={index}>
          <button onClick={() => this.jumpTo(index)}>{desc}</button>
        </li>
      )
    })

    let status
    if (winner) {
      status = 'winner is:' + winner + '!!!!'
    } else {
      status = 'Next player:' + (this.state.xIsNext ? 'x' : 'o')
    }

    return (
      <div className="game">
        <div className="game-board">
          <Board
            squares={current.squares}
            onClick={(i) => this.handleClick(i)} />
        </div>
        <div className="game-info">
          <div>{status}</div>
          <ol>{moves}</ol>
        </div>
      </div>
    );
  }
}

// ========================================

ReactDOM.render(
  <Game />,
  document.getElementById('root')
);

function calculateWinner(squares) {
  const lines = [
    [0, 1, 2],
    [3, 4, 5],
    [6, 7, 8],
    [0, 3, 6],
    [1, 4, 7],
    [2, 5, 8],
    [0, 4, 8],
    [2, 4, 6],
  ];
  for (let i = 0; i < lines.length; i++) {
    const [a, b, c] = lines[i];
    if (squares[a] && squares[a] === squares[b] && squares[a] === squares[c]) {
      return squares[a];
    }
  }
  return null;
}